Is it necessary to unsubscribe if classB is one classA created, and classA is being disposed? Will the reference held by classA prevent classB from being garbage collected?
it_saige
No it won't but say that the subscription to classB's event uses unmanaged resources, you already stated that classB does not implement IDisposable, so the only way to sensible way to free those unmanaged resources would be by unsubscribing the event, as long as the event unsubscription process handles the freeing of those unmanaged resources, which from a design standpoint, is sensible.